LAUSR

The aim of the study was to investigate whether increased inclusion of sugar beet pulp alters retention of fat, protein, and energy when backfat are restored in early and mid gestation. In total, 46 sows were fed one of four treatments with increasing inclusion of sugar beet pulp with dietary fiber levels of: 119, 152, 185, and 217 g/kg;, sows were assigned to one of three feeding strategies (high, medium and low) depending on backfat thickness at mating and again at day 30 for the following month. At day 0, 30, 60, and 108, body weight and backfat thickness were measured and body pools of protein and fat were estimated using the deuterium technique. At day 30 and 60, urine, feces and blood samples were collected to quantify metabolites, energy, and N balances. At day 15 and 45, heart rate were recorded to estimate the heat production. At farrowing, total born and weight of the litter were recorded. In early gestation, body weight gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. Increase in backfat was greatest for sows fed the high feeding strategy, intermediate when fed the medium strategy, and negligible for sows fed the lowest feeding strategy. N intake, N loss in feces and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly, and total metabolizable energy intake therefore increased from 40.5 MJ ME/d in the low fiber group to 43.5 MJ ME/d in the high fiber group (P < 0.001). Changing the metabolizable energy towards more ketogenic energy was expected to favour fat retention rather than protein retention. However, due to increased intake of metabolizable energy and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased dietary fiber concentration increased protein retention.